The Analysis, Based On Aerial Images Of Three-dimensional Positioning And Accuracy

Creating three-dimensional(3-D)models of real urban objects is an important goal in a wide variety of application. This paper describe a method that utilizes airborne laser profilers and aerial images for the 3-D reconstruction of urban objects. Error analysis of the system an precision evaluation based on the obtained equations for control points are given.Firstly, the theory of binocular stereo imaging is introduced and the relation of relative orientation between two cameral , during the process of imaging is discussed.Secondly, according to the practical engineering requirement, using new sensors as combined systems, the effort for the acquisition of control points to determine the absolute orientation could be minimized or even avoided. Beside the airborne camera, GPS, two laser profilers and an inertial system are used as additional sensors. The laser profilers are looking sidewards, so that during the stripewise flight over the photogrammetric block laser profiles at the upper and lower border of the strip are recorded. GPS and INS-Data are registered during the whole time of the flight. Using this method there is following additional information for each image pair. The absolute orientation of an image pair could be performed without using additional control points.Image matching is one of the most fundamental processes in geopositioning from multi-images. Least squares matching and cross correlation matching are the most basic and popular techniques applied by photogrammetrists . This paper resents the initial results of these two image maching techniques. The least squares matching and cross correlation matching are applied to the airborne sequence images, and the characteristics and results of applying the matching techniques arediscussed.After image matching, we can get homonymy points from airborne sequences images, through using Virtuouz software we could acquire 3-D models of urban objects.Finally, combing with practical engineering, we carry out the simulation computation. This paper provides the detail procedure for the positioning accuracy analysisand concluding remarks are given. The simulation computation indicates that the results of this paper have importance to practical application.